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Patrick Turner Patrick Turner is offline
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Default Grounded Grid?? Really?

True, & true.

HOWEVER: a couple of times I have made myself look godlike (and that is a vast stretch even to the best of imaginations) to a certain class of audiophile by the simple expedient of connecting their speakers correctly (in phase). On one very special occasion, I had to practically tie one gentleman down as he INSISTED that the right speaker should be connected one way, the left the other way. Until he heard them connected properly.

So, relative phase angles may be inaudible. But 180 degrees out of phase is most definitely audible.
- hide quoted text -

Peter Wieck
Melrose Park, PA

Phase and audiophiles are not happy marriage material. Phase is a bad word, because ppl talk in terms of being un-phased as a negative experience, and of course NFB is also evil, because its damned negative, and saying it ought to be called "inverse feedback" simply makes audiophiles feel queasy about listening to music standing upside down, or mounting their amps upside down, ie, something must be inverted to counter the inverted NFB.

I don't know how many times I corrected phase for sub-woofers which wen connected by the audiophile made overall bass worse, while putting in an unwanted boom below 30Hz. Measurements at the listening chair were usually appalling, only able to be improved marginally.

It is standard practice by hundreds of speaker manufacturers to have phase of bass and tweeter with "normal" phase, then with midrange deliberately "reverse phase" connected. I've done it myself in nearly all 3 way speakers I made.
One will find it is THE WAY to get a smooth transition of response between bass-mid, and between mid-tweeter, when correctly damped C&L second order crossover filters are used.

Its stupid to worry that the midrange is 180d to bass and tweeter. The essential thing is a flat response, and SAME phase shift of L and R speakers in order to get the best stereo imaging. The only time I have heard any one tell me they didn't like the phase behavior of a speaker was because L and R had different measurements, or someone has replaced a driver and one speaker driver was wrongly phased, and then they couldn't understand why a singer seems to be to the left of a LEFT speaker, when we all know she was standing centre stage when recorded.

Music produced at a live venue has instruments placed at many different distances to our ears, and yet it makes SFA difference if the musos change distance by plus or minus maybe several or dozens of wavelengths, so we never ever can hear music at our ear without the phase analomies occurring because of varied path length. Much sound indoors is reflected, there is a huge amount if phase cancellations and additions, but they sum to give an average level, and its no use thinking about it all because it'd lead to maths equations that are too complex to have meaning, even if worked on with super computer. So what you hear is what you get, and live music needs a nice venue not too reverberent,
and we also need a good room to reproduce that overall "room atmosphere" - and remarkably, if some extra phase jiggery-pokery is added in speaker making, but speakers are good quality, we really do hear what we heard live at the venue.

Scientific American did tests back in 1950s or 60s to find out if ppl could hear phase change. Nobody could. You play music with speaker leads reversed at amp or normal, and nobody could pick it.

But audiophiles are so often not at all scientifically minded, and go through life never ever understanding any formula or technical concept. They will often claim to hear or not hear some peculiar thing in their systems, without their being the slightest real evidence to cause the perceived phenomena, and gently I have had to just demonstrate by doing and measuring and comparing to put them at ease - until next time they find a reason to change amps or speakers. I have surprised myself when I improved total quality of what I made over a number of years which made it easier to sell my gear. If the audiophiles liked what I made, and if they changed houses and it all still sounded well, then that WAS really something.

Oh, and BTW, just about all recorded music has huge post recording processing done on the music, often digitally, and STILL we get some excellent recordings that are so good the word PHASE just never enters our mind.

Patrick Turner.